1. Field of the Invention
The present invention relates to an anchor device for a seat belt for connecting a webbing to a vehicle body for restraining an occupant to a seat so that a load applied to the webbing is received by the vehicle body.
2. Description of the Prior Art
There are seat belt systems for restraining an occupant by a webbing upon collision of a vehicle, which include means for absorbing a shock by slightly moving or stretching the webbing in a direction in which a load is applied. Such seat belt systems have been proposed in Japanese Utility Model Application Laid-open No. 104464/91, Japanese Utility Model Publication No. 13247/90 and Japanese Utility Model Application Laid-open No. 114465/89.
The seat belt system described in Japanese Utility Model Application Laid-open No. 104464/91 is made by overlapping and sewing a loose portion formed in a portion of the webbing. In this seat belt system, the sewn portion is broken by a shock to stretch the webbing, thereby exhibiting a shock absorbing effect.
In the seat belt system described in Japanese Utility Model Publication No. 13247/90, a bead-like bent portion is formed on a floor panel of a vehicle body, to which an anchor for locking the webbing is fixed. In this system, the bead-like bent portion is stretched by a shock to move the webbing, thereby exhibiting a shock absorbing effect.
In the seat belt system described in Japanese Utility Model Application Laid-open No. 114465/89, a loop-like opening is defined in an anchor to intersect, at right angle a direction of extension of the webbing. In this system, the opening is deformed by a shock to move the webbings thereby exhibiting a shock absorbing effect.
To cause such seat belt systems to exhibit an effective shock absorbing effect, it is necessary to properly set the magnitude of a load, in the moment when the movement of the webbing is started, and to properly set the amount of movement of the webbing and the load of such movement. However, any of the prior art seat belt system suffers from a problem that such setting is difficult.